Authors

Eric L. Nielsen (1), Laird M. Close (1), Michael Liu (2), Beth A. Biller (2), Zahed Wahhaj (2)

Affiliations

(1) Steward Observatory, University of Arizona; (2) Institute for Astronomy, University of Hawaii

Abstract

Despite recent successes, imaging extrasolar planets continues to be extremely challenging, with most surveys for planetary mass companions to nearby stars returning null results. By carefully considering these null results from multiple surveys, we have placed statistical constraints on the populations of extrasolar giant planets around stars of a solar mass or less. We have performed a uniform analysis of the null results from a VLT NACO broadband NIR survey (Masciadri et al. 2005), the VLT and MMT Simultaneous Differential Imaging (SDI) survey (Biller et al. 2007), and the Gemini Deep Planet Survey (Lareniere et al. 2007), using both the "hot start" models of planetary flux as a function of age and mass of Burrows et al. (2003) and Baraffe et al. (2003), as well as the newer core-accretion based models of Fortney et al. (2008). Our analysis shows that for FGKM stars, a model for extrasolar giant planets with power-laws for mass and semi-major axis as given by Cumming et al. (2008) cannot, with 95% confidence, have planets beyond 65 AU. We demonstrate the importance of considering past null results when designing future surveys, by considering the Near Infrared Coronagraphic Imager (NICI) survey, currently underway at the Gemini South Telescope. By designing a target list that incorporates the lessons of previous null results, we maximize our chances of detecting extrasolar planets, while ensuring that even a null result from the NICI survey will be of great scientific interest, placing even more stringent constraints on the population of extrasolar giant planets around Sun-like stars.